|
Title:
|
Grazing effects on the species-area relationship: Variation along a climatic gradient in NE Spain
|
|
Author:
|
de Bello, Francesco; Leps, Jan; Sebastià, Ma. T.
|
|
Notes:
|
Questions: Does grazing have the same effect on plant species
richness at different spatial scales? Does the effect of spatial
scale vary under different climatic conditions and vegetation
types? Does the slope of the species-area curve change with
grazing intensity similarly under different climatic conditions
and vegetation types?
Location: Pastures along a climatic gradient in northeastern
Spain.
Methods: In zones under different regimes of sheep grazing
(high-, low-pressure, abandonment), plant species richness
was measured in different plot sizes (from 0.01 to 100 m2)
and the slope of the species-area curves was calculated. The
study was replicated in five different locations along a climatic
gradient from lowland semi-arid rangelands to upland moist
grasslands.
Results: Species richness tended to increase with grazing
intensity at all spatial scales in the moist upland locations.
On the contrary, in the most arid locations, richness tended to
decrease, or remain unchanged, with grazing due to increased
bare soil. Grazing differentially affected the slope (z) of the
species-area curve (power function S = c Az
) in different
climatic conditions: z tended to increase with grazing in arid
areas and decrease in moist-upland ones. β-diversity followed
similar pattern as z.
Conclusions: Results confirm that the impact of grazing on
plant species richness are spatial-scale dependent. However,
the effects on the species-area relationship vary under different
climatic conditions. This offers a novel insight on the patterns
behind the different effects of grazing on diversity in moist vs.
arid conditions reported in the literature. It is argued that the
effect of spatial scale varies because of the different interaction
between grazing and the intrinsic spatial structure of the
vegetation. Variations in species-area curves with grazing along
moisture gradients suggest also a different balance of spatial
components of diversity (i.e. α- and β-diversity).
The research was partly funded by grants to FdB from the University of Nuoro, the Government of Catalonia (DURSI; FI-2002-2004 programme) and was partially developed within the CARBOCAT and CARBOPAS projects. The Fundació Territori i Paisatge facilitated field sampling in the Alinyà Valley. Participation of JL in this study was partially supported by the MSMT 600-766-5801 grant. |
|
Subject(s):
|
-Competition
-Heterogeneity
-Land use
-Management |
|
Rights:
|
(c) IAVS; Opulus Press Uppsala, 2007
info:eu-repo/semantics/restrictedAccess |
|
Document type:
|
article
publishedVersion |
|
Published by:
|
Wiley
|
|
Share:
|
|
